This topic describes differences in features and limits between enhanced NAT gateways and standard NAT gateways.
Comparison of features
| Feature | Enhanced NAT gateway | Standard NAT gateway | Reference |
|---|---|---|---|
| Multiple NAT gateways for one virtual private cloud (VPC) | Supported | Not supported | Create a NAT gateway |
| Attach a NAT gateway to a vSwitch | Supported | Not supported | |
| Billed on an hourly basis | Supported | Not supported | Pay-as-you-go |
| Process TCP, UDP, and ICMP segments | Supported | Not supported | N/A |
| Metric | 22 | 4 | Use Cloud Monitor to monitor NAT gateways |
| Network traffic monitoring (TOP ECS) | Supported | Not supported | View monitoring data |
| Associate multiple elastic IP addresses (EIPs) with a NAT gateway | Supported | Supported | Associate an EIP with a NAT gateway |
| SNAT | Supported | Supported | Create a SNAT entry to access the Internet |
| Create multiple SNAT entries in a SNAT table | Supported | Supported | Create a SNAT entry to access the Internet |
| Associate multiple EIPs with a SNAT table | Supported | Supported | |
| DNAT | Supported | Supported | Create a DNAT entry to provide Internet-facing services |
| DNAT port mapping | Supported | Supported | Create a DNAT entry to provide Internet-facing services |
| DNAT IP mapping | Supported | Supported | |
| Billed on a daily basis | Not supported | Supported | Pay-as-you-go |
| ECS instances use SNAT to access services that use DNAT to provide external access when the same enhanced NAT gateway is used for SNAT and DNAT | Not supported | Supported | Use SNAT of enhanced NAT gateways to enable ECS instances to access services that use DNAT to provide external access in the same VPC |
Comparison of limits
| Item | Enhanced NAT gateway | Standard NAT gateway |
|---|---|---|
| The maximum number of NAT gateways that can be created for a VPC | 5. To increase the quota, submit a ticket. | 1 (not adjustable) |
| Use an EIP for both SNAT and DNAT | Only selected users can use an EIP for both SNAT and DNAT. To apply to be added to a whitelist, submit a ticket. | Not supported (not adjustable) |
| The maximum number of DNAT entries that can be added to a NAT gateway | 100. You can increase the quota. For more information, see Quota management. | 100. You can increase the quota. For more information, see Quota management. |
| The maximum number of SNAT entries that can be added to a NAT gateway | 40. You can increase the quota. For more information, see Quota management. | 40. You can increase the quota. For more information, see Quota management. |
| The maximum number of EIPs that can be specified in a SNAT entry | 64 (not adjustable) | 64 (not adjustable) |
| Create a NAT gateway for a VPC that contains a custom route entry whose destination CIDR block is 0.0.0.0/0 | Supported | Not supported. You must delete the custom route entry whose destination CIDR block is 0.0.0.0/0 before you can create a NAT gateway for the VPC. |
| Limits on a vSwitch by the maximum bandwidth of the EIPs specified in the SNAT entry that is added to the vSwitch | Yes. If the EIP is associated with an EIP bandwidth plan, the vSwitch is limited by the maximum bandwidth of the EIP bandwidth plan. | Yes. If the EIP is associated with an EIP bandwidth plan, the vSwitch is limited by the maximum bandwidth of the EIP bandwidth plan. |
| The maximum number of EIPs that can be associated with a NAT gateway | 20. You can increase the quota. For more information, see Quota management. | 20. You can increase the quota. For more information, see Quota management. |
| The maximum number of pay-by-data-transfer EIPs that can be associated with a NAT gateway | 10. You can increase the quota. For more information, see Quota management. | 10. You can increase the quota. For more information, see Quota management. |
| The maximum bandwidth supported by a pay-by-data-transfer EIP that is associated with a NAT gateway | 200 Mbit/s (not adjustable) | 200 Mbit/s (not adjustable) |
| The maximum bandwidth of a NAT gateway | 5 Gbit/s. If the total bandwidth of the EIPs or EIP bandwidth plans is greater than 5 Gbit/s, submit a ticket to increase the quota. | A NAT gateway does not have a bandwidth limit. The bandwidth limit depends on the
bandwidth of the EIPs that are specified in a SNAT entry or a DNAT entry, and the
bandwidth of the EIP bandwidth plans to which the EIPs are added.
For example, you create a SNAT entry for a NAT gateway, and specify five pay-by-data-transfer EIPs and two pay-by-bandwidth EIPs with 500 Mbit/s bandwidth each in the SNAT entry. The bandwidth of the NAT gateway is limited to 2,000 Mbit/s. This value is based on the following calculation: 5 × 200 Mbit/s + 2 × 500 Mbit/s = 2,000 Mbit/s. If the seven EIPs are added to the same EIP bandwidth plan, and the bandwidth of the EIP bandwidth plan is limited to 1,000 Mbit/s, the bandwidth limit of the NAT gateway is 1,000 Mbit/s. |
| The maximum number of concurrent connections for an EIP is 55,000. | Yes | Yes |
| The maximum bandwidth of an EIP in an EIP bandwidth plan is 200 Mbit/s. | No | Yes |
| Users of NAT service plans are not allowed to associate EIPs with NAT gateways. | Yes | Yes |
| Transient connection errors may occur when you change the maximum bandwidth of the EIP bandwidth plan that is associated with a NAT gateway. For example, you can upgrade the maximum bandwidth from less than 1 Gbit/s to greater than 1 Gbit/s, or downgrade the maximum bandwidth from greater than 1 Gbit/s to less than 1 Gbit/s. | No | Yes |
| Transient connection errors may occur when IP addresses in the existing SNAT entries are reduced. | Yes | Yes |
| Transient connection errors may occur when IP addresses in the existing SNAT entries are increased. | No | Yes |